A cot is one of the few places a small baby spends hours unsupervised. The good news is the safety rules are short and consistent across the AAP, NHS, Lullaby Trust, and CPSC: keep the cot empty except for a fitted sheet on a firm mattress, dress the baby for the room temperature, and put them on their back.
Most parents already know that. Where things go wrong is in the comfort items the cot keeps acquiring — a positioner that came as a gift, a fluffy blanket from the in-laws, a sleep pod marketed as "safe", a bumper for "looks". This is the running list of what comes out, what stays in, and why.
Healthbooq emphasizes the importance of keeping cribs clear of hazardous items.
What stays in the cot
That's the entire list:
A firm, flat mattress that fits the cot frame with no more than a 3 cm gap on any side (NHS guidance). Firm enough that pressing your hand into it leaves no indent. Waterproof cover is fine.
One fitted sheet, snug at all four corners. No flat sheets — they migrate.
The baby, dressed for the room. A sleep bag (a wearable blanket, no hood, no sleeves longer than the arms) sized to the baby's weight. The TOG rating to use depends on the room temperature, which should sit between 16°C and 20°C. The Lullaby Trust publishes a temperature-and-tog chart that's worth bookmarking.
A pacifier, if used — loose, not on a clip or string. Offered at the start of sleep, no need to replace if it falls out. Pacifier use during sleep is associated with a small reduction in SIDS risk; the strings and clips that come with them are not safe in the cot.
A swaddle, only for the very young, only until rolling begins. A swaddled baby left to roll prone is a dangerous combination — they can't get their face off the mattress with arms pinned. Stop swaddling at the first sign of rolling, usually 3–4 months. After that, transition to a sleep bag with arms out.
That's it. A cot containing those things and nothing else is operating exactly as designed.
What comes out
Pillows. Suffocation risk in any infant; not needed for comfort or position. Pillows belong in toddler beds from around age two, not in cots.
Loose blankets and quilts. They cover faces, get kicked off, get pulled up. Sleep bag instead. If a blanket is unavoidable for some reason, light, breathable, tucked firmly below the armpits, no higher than chest level — but a sleep bag is simpler and safer.
Cot bumpers, mesh liners, padded liners — all of them. Originally sold to prevent limbs slipping through slats; now associated with suffocation, entanglement, and strangulation deaths and a measurable increase in SIDS risk. Banned outright in the US (Safe Sleep for Babies Act, 2022) and recommended against by every UK and US infant sleep authority. Modern cots have correctly spaced slats (less than 6.5 cm apart per BS EN 716) — the original problem they "solved" is no longer a problem. If you have inherited bumpers, throw them out, don't pass them on.
Sleep pods, "nests", positioners, anti-roll wedges. Marketed as cosy or safe; not safe to sleep in. The AAP and Lullaby Trust both advise against them. Babies have suffocated in pods placed in cots and on adult beds. There is no positioner that has been shown to reduce SIDS, and several have been recalled after deaths.
Stuffed animals and soft toys. Potential face-coverage and a SIDS risk factor; offer them outside the cot during awake play instead. After the first birthday a single small comfort item is usually fine; under one, no.
Hard toys, teethers, books. Anything that can land on the baby's face when they shift, or be mouthed and broken. Out.
Mobiles and hanging attachments. Fine in the early months when they're decorative and out of reach. Take them down by 5 months — the moment a baby can grab one is the moment it becomes a strangulation/falling-on-the-baby hazard.
Pacifier clips, strings, ribbons, bibs, swaddles with ties. Anything with a string longer than about 18 cm in or near the cot is a strangulation risk. Bibs come off before sleep.
Cords from anything outside the cot. No part of a blind pull-cord, baby monitor cord, charger cable, or curtain tie should be reachable from the cot. Move the cot if you have to. Looped blind cords are an underrated cause of strangulation deaths.
A crib mattress topper. Not a thing. A topper compromises the firmness that makes the mattress safe. The baby doesn't need it; firmness is a feature, not a defect.
"But the gift has already arrived…"
A few specific items keep showing up because they're popular gifts:
- The DockATot / Snuggle Nest / sleep pod. Use only for awake supervised lounging if at all; never for sleep, never in the cot, never in your bed. Manufacturers have started saying this themselves under regulatory pressure.
- The cute set with bumpers and quilt. The cot sheet is the only safe item in the set. Hang the bumpers somewhere else as a wall feature if it helps; they're not for the cot.
- The wedge to "stop reflux". No wedge has been shown to help reflux and they introduce a fall and suffocation risk. Reflux improves with age, not products.
- The weighted sleep sack. Recalled by major retailers and discouraged by the AAP — weighted layers compress the chest and are linked to deaths.
When to remove what
- Mobile: before the baby can sit up and grab — typically by 5 months.
- Swaddle: at the first sign of rolling — usually 3–4 months. Move to an arms-out sleep bag.
- Bumpers: today, if any are still there.
- Cot itself: when the baby can climb out, or reaches around 90 cm tall, transition to a toddler bed or sidecar arrangement.
A simple rule for any new item
If you find yourself wondering whether a thing belongs in the cot, ask:
- Is it the firm flat mattress, a fitted sheet, the baby, or a sleep bag?
If no, the answer is no. The empty look is the safe look — boring is the goal.
Key Takeaways
A safe cot contains a firm flat mattress, a tight-fitting sheet, and a baby in appropriate sleepwear. Optionally a pacifier (no string) and, for very young infants only, a swaddle until rolling begins. Everything else — pillows, bumpers, blankets, pods, positioners, stuffed animals — increases SIDS or suffocation risk and should not be in there.
